The invention relates to a support for supporting a substrate in a chamber and related methods.
In the manufacture of integrated circuits, a substrate is processed by a plasma of process gas in a chamber. The substrate is typically supported in the chamber by a support, a portion of which may comprise a dielectric material covering an electrode. The electrode may be charged to electrostatically hold the substrate, to energize the process gas in the chamber, or to do both. In addition, the support may comprise a heater to heat the substrate, or a heat exchanger, such as for example, channels through which heat transfer fluid may be circulated to heat or cool the substrate. In addition, a heat transfer gas, such as helium, may be introduced through a conduit in the support to below the substrate to enhance heat transfer rates to and from the substrate.
The substrate fabrication process may be performed at elevated temperatures and using erosive gases. Temperatures exceeding 100xc2x0 C. in combination with gases such as halogen gases may result in rapid thermal degradation of the support. The erosion and temperature resistance may be met by using supports comprising polymer or ceramic materials, such as for example, polyimide, aluminum oxide and aluminum nitride. However, it is difficult to attach the polymer or ceramic supports to the chamber which is typically made from a metal. For example, differences in thermal expansion coefficient between the support and the chamber may cause thermal expansion stresses that result in cracking or fracturing of either structure.
Another problem that often occurs with conventional supports arises because the heat transfer gas passed through a conduit in the support may leak out from joints in the conduit. A loss in pressure of the heat transfer gas during processing may cause non-uniform heat transfer rates, and consequently non-uniform temperatures, across the substrate. It is desirable to maintain uniform heat transfer rates and temperature differentials across the substrate during its processing, otherwise, the substrate may be processed unevenly.
Therefore, it is desirable to have a support that may be used at elevated temperatures without excessive thermal expansion stresses. It is further desirable to maintain uniform heat transfer rates and temperature differentials across a substrate during its processing. It is also desirable to pass heat transfer gas through the support without excessive leakage of the gas.
The present invention satisfies these needs. In one aspect, the invention comprises support capable of supporting a substrate in a chamber. The support comprises a plurality of sections that may be joined to one another or to the chamber, at least one of the sections comprising a surface adapted to receive a substrate, and first and second bonds between the sections or between a section and the chamber, the first bond comprising a first bonding material and the second bond comprising a second bonding material.
In another aspect of the invention, a substrate processing chamber comprises a substrate support comprising a plurality of sections connected to one another by first and second bonds, wherein the first bond comprises a first bonding material and the second bond comprises a second bonding material. The processing chamber further comprises a gas distributor, a gas energizer, and a gas exhaust, whereby a substrate received on the support may be processed by gas introduced through the gas distributor, energized by the gas energizer, and exhausted by the gas exhaust.
In another aspect of the invention, a substrate support comprises a first, second, and third section, the first section comprising a surface adapted to receive a substrate, and a first bond between the first and second sections and a second bond between the second and third sections, wherein the first bond comprises a first bonding material capable of bonding surfaces when heated to a first temperature and the second bond comprises a second bonding material capable of bonding surfaces when heated to a second temperature.
In another aspect of the invention a method of forming a substrate support comprises forming first, second, and third sections, the first section comprising a surface adapted to receive a substrate, providing a first bonding material between the first and second sections, and providing a second bonding material between the second and third sections.
In another aspect of the invention, a method of forming a substrate support comprises forming a plurality of sections with first and seconds bonds between the sections or between a section and a chamber, one of the sections comprising a surface adapted to receive a substrate, and heating the first bond to a first temperature and heating the second bond to a second temperature.